1: This is our presentation on Computational Hydrographic Printing, which we had all heard about. We wanted to explore it in more depth and detail seeing how it actually works , and what possible applications for it are.

2: What is Hydrographic Printing? It is a well known technique that transfers colour onto a film and then onto an object. It can be used on alloy wheels to wrap them, statues, masks… so it works on a wide range of materials.

3: There’s a vat water, a film (with the texture printed on it) is placed on the water surface, the film is then softened with a chemical and the objects is then dipped into the water through the film, which wraps around the object and adheres to the surface.

4: Disadvantages with the traditional process;

Difficult to line the texture up with the objects surface accurately

Complex object geometries can cause the film to tear/distort

Limited to repetitive patterns, so creativity is impeded

5: So what is Computational Hydrographic Printing? Algorithms run a simulation of the hydrographic process with the user inputting the object’s geometry and desired texture design. The simulation then shows where points on the film align with the objects surface.

Developed software to simulate stretching from the objects given immersion

7: After the simulation has ran, the object is placed in a mechanical gripper, with the orientation fixed, then it is dipped into the vat and the film adheres to the surface of the object.

8: The immersion is controlled by mechanical apparatus and this measured by a 3D vision system. (Take some time to look at image and explain process)

9: By modelling the film floating in the water, the stretch and distortion can be predicted numerical simulation to make a map making sure the texture being applied to the model is exact.

10: The speed that the object will be dipped in is a known value and is automated, the point at which it enters the water is measured by a 3D vision system along with the orientation, the thickness of the film with image printed on is actually estimated, but all of this enables the amount of stretching the film will undergo and therefore apply it accurately to the object.

11: Advantages:

Provides greater accuracy

Built using off-the-shelf hardware so anyone can buy the hardware and set this up

This also makes the process cheaper

12:Advantages Continued:

Allows for multiple immersions will be explained later

It gives the user greater flexibility in their designs – they aren’t restricted to repetitive patterns and are free to be more creative

13: Video of process: 1.42 – 2.02

14: A well known technique used to transfer ink onto a thin film which is attached to the surface of a 3D object is Hydrographic Printing or Traditional Hydrographic Printing. Because it involves printing a pixel image onto PVA film which is placed on top of water. It is also known is Hydroprinting or Water Transfer printing.

15: BUT no focus on fabrication colours

16: When dipping once, it can stretch the film too much and cause the colours to lighten. Multiple immersion works because the film (when not printed upon) is transparent so when it sticks the object it doesn’t impact its appearance and then the orientation can be altered to apply more film to other places.

17: Multiple immersion has the advantage of using less stretched colour films to colour the object surface but a small calibration error in the printing process can lead to gaps or seams at the edges of the film. This is solved by fading out texture regions at boundaries.

18: The future:

Making it a completely automated process without the user needing to adjust the object’s orientation

To increase the accuracy of colour blending by creating a model which would calculate the colour blending deviation

19: The future continued:

Avoid the issue of colours getting lighter from being stretched by adding more ink to the highly stretched areas – but this adds to the thickness of the film

Avoid estimating the film thickness by using a CMYKW-based printer which produces a uniform thickness

Above are my notes on Computational Hydrographic Printing that I made from the SIGGRRAPH 2015 journal. I explained the process of Computational Hydrographic Printing twice because I was thinking of how to word it- but I have decided to go with the first explanation that I wrote out.